基于3S技术的闽江流域水土流失定量评价

Quantitative Estimation of Water and Soil Erosion From Minjiang Watershed Based on Geomatics

结合遥感(RS)、地理信息系统(GIS)及卫星导航系统(GPS)技术对美国通用水土流失模型(USLE)中的土壤主要侵蚀因子的计算方法进行了探讨,利用闽江流域2003年遥感影像解译数据、统计资料和实地考察数据,对闽江流域水土流失进行了定量分析,结合研究确定的土壤侵蚀模数分级标准对闽江流域水土流失进行了定量评价.结果表明:闽江流域土壤侵蚀总面积为29470.68 km2,占流域面积的48.32%;流域依上游、中游、下游的顺序,各区段微度和极强度以上侵蚀呈下降的趋势,而轻度、中度和强度侵蚀呈现上升的趋势;闽江流域上游水土流失状况,微度侵蚀比重呈现沙溪>建溪>富屯溪,而轻度、强度和极强度以上侵蚀呈现沙溪<建溪<富屯溪.

By using the combined technologies of remote sensing （RS）, geographic information system （GIS） and global position system （GPS）, the paper conducted a probe into the algorithm of the main soil-erosion factors in the ULSE model used in USA; by using the interpreted data from the RS images, the statistics and the in situ data, of Minjiang Watershed in 2003, the paper made a quantitative analysis of its water-soil loss; and by using an already-determined hierarchy standard of the erosion modulus, the paper finally carried out an evaluation of the soil erosion of the watershed. Results show that the total erosion area is 29 470. 68 km^2 which accounts for 45.18% of the whole watershed; that according to the sequence of upper, middle and lower reaches, the erosion of each reach of the weakest and strongest degree takes on a falling trend while that of the weak, middle and strong degree does a rising one; and that in its upper reaches, the weakest erosion goes from big to small as the following order shows： Shaxi 2〉 Jianxi 2〉 Futunxi, while the weak, strong and strongest erosion goes vice versa： Shaxi 〈 Jianxi 〈 Futunxi.